Composite Lymphoma Comprising Extranodal NK/T-Cell Lymphoma and Diffuse Large B-Cell Lymphoma

Area of Science:

• Hematology
• Oncology
• Pathology

Background:

• Composite lymphomas are rare neoplasms characterized by the coexistence of two or more distinct lymphoma types within the same patient.
• Extranodal NK/T-cell lymphoma, nasal type (ENKL) and diffuse large B-cell lymphoma (DLBCL) are distinct lymphoid malignancies with different clinical behaviors and treatment responses.
• The simultaneous occurrence of ENKL and DLBCL as a composite lymphoma has not been previously documented.

Observation:

• A 70-year-old male presented with fatigue and was diagnosed with a composite lymphoma.
• Computed tomography revealed pulmonary consolidations, leading to a diagnosis of ENKL via transbronchial lung biopsy.
• Positron emission tomography identified gastric involvement, and subsequent gastroscopy confirmed DLBCL.

Findings:

• The patient received two courses of chemotherapy including rituximab, which resulted in a reduction of DLBCL.
• However, the ENKL component demonstrated resistance to the treatment and progressed.
• This case represents the first reported instance of concomitant ENKL and DLBCL in a composite lymphoma.

Implications:

• This rare presentation highlights the complexity of composite lymphomas and the need for accurate diagnosis of each component.
• The differential treatment response observed suggests that distinct therapeutic strategies may be required for each lymphoma type within a composite neoplasm.
• Further research is warranted to understand the pathogenesis and optimal management of such rare composite lymphomas.